Henry Augustus Rowland | |
|---|---|
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| Born | (1848-11-27)November 27, 1848 Honesdale, Pennsylvania, U.S. |
| Died | April 16, 1901(1901-04-16) (aged 52) |
| Alma mater | Rensselaer Polytechnic Institute |
| Known for | Diffraction grating Rowland circle Rowland ring |
| Awards | Rumford Prize (1883) Henry Draper Medal (1890) Matteucci Medal (1895) |
| Scientific career | |
| Fields | Physicist |
| Institutions | University of Wooster Rensselaer Polytechnic Institute Johns Hopkins University |
| Academic advisors | Hermann von Helmholtz |
| Doctoral students | Joseph Sweetman Ames Louis Bell Edwin Hall William Jackson Humphreys Charles Elwood Mendenhall Harry Fielding Reid Albert Francis Zahm |
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Henry Augustus Rowland (November 27, 1848 – April 16, 1901) was an Americanphysicist and Johns Hopkins educator. Between 1899 and 1901 he served as the first president of theAmerican Physical Society. He is remembered for the high quality of thediffraction gratings he made and for the work he did with them on the solar spectrum.
Rowland was born inHonesdale, Pennsylvania, where his fatherHenry Augustus Rowland was aPresbyterian pastor.[1] His mother, Harriette Heyer, the daughter of a wealthy New York merchant, was ofKnickerbocker descent.[2] From an early age, the younger Rowland exhibited marked scientific tastes and spent his spare time in electrical and chemical experiments.
He graduated fromRensselaer Polytechnic Institute inTroy, New York in 1870.
After college, Rowland worked for the Western New York railway, but he did not like the work. He became an instructor in natural science at theUniversity of Wooster inWooster, Ohio. He resigned in order to return to Troy as assistant professor of physics at Rensselaer.
Rowland was considered one of the most brilliant American scientists of his day. However, initially his merits were not perceived in his own country. He was unable to secure the publication of many of his early scientific papers; butJames Clerk Maxwell at once saw their excellence, and had them printed inPhilosophical Magazine. When the managers ofJohns Hopkins University inBaltimore,Maryland, asked advice in Europe as to whom they should make their professor of physics, Rowland was overwhelmingly recommended as the best choice. In 1876, he became the first occupant of the chair of physics at Johns Hopkins University, a position which he retained until his death in Baltimore on April 16, 1901.[3]
In the interval between his selection to Johns Hopkins and the assumption of his duties there, he studied physics underHermann von Helmholtz in Berlin (1875–76),[4][5][6] and carried out a well-known research on the effect of an electrically charged body in motion, showing it to give rise to a magnetic field.[7][8]
After settling in Baltimore, Rowland focused on two important pieces of work. One was a redetermination of theohm.[9] For this he obtained a value which was substantially different from that ascertained by the committee of theBritish Association appointed for the purpose, but ultimately he had the satisfaction of seeing his own result accepted as the more correct of the two. The other was a new determination of the mechanical equivalent of heat.[10][11] In this he usedJ. P. Joule's paddle-wheel method, though with many improvements, the whole apparatus being on a larger scale and the experiments being conducted over a wider range of temperature. He obtained a result distinctly higher than Joule's final figure. Additionally, he made many valuable observations on the thermodynamics involved, and on the variation of the specific heat of water, which Joule had assumed to be the same at all temperatures.
In 1882, before thePhysical Society of London, Rowland gave a description of thediffraction gratings,[12][13] with which his name is specially associated,[a] and which have been of enormous advantage to astronomical spectroscopy. These gratings consist of pieces of metal or glass ruled by means of a diamond point with a very large number of parallel lines, on the extreme accuracy of which their efficiency depends. For their production, therefore, dividing engines of extraordinary trueness and delicacy were required, and in the construction of such machines Rowland's engineering skill brought him conspicuous success. The results of his labors may be found in the elaboratePhotographic Map of the Normal Solar Spectrum (1888) and theTable of Solar Wave-Lengths (1898).
In his later years, Rowland was engaged in developing a system of multiplextelegraphy. He authoredA Plea for Pure Science, in 1883 an important document for the understanding of the relationship between science in university and in commercial contexts in the late nineteenth and early twentieth century.[14]
Rowland was elected to theAmerican Academy of Arts and Sciences in 1876.[15] TheNational Academy of Sciences, of which Rowland was a member, awarded him theHenry Draper Medal in 1890 for his contributions toastrophysics,[16][17] he was elected to honorary membership of theManchester Literary and Philosophical Society, in 1894.[18] He won theMatteucci Medal in 1895. In 1896, he was elected to theAmerican Philosophical Society.[19] Also, theHenry August Rowland House in Baltimore was designated aNational Historic Landmark.
This article incorporates text from a publication now in thepublic domain: Chisholm, Hugh, ed. (1911). "Rowland, Henry Augustus".Encyclopædia Britannica (11th ed.). Cambridge University Press.
Works by or aboutHenry Augustus Rowland atWikisource